The formation of wide exoKuiper belts from migrating dust traps

Abstract

The question of what determines the width of Kuiper belt analogues (exoKuiper belts) is an open one. If solved, this understanding would provide valuable insights into the architecture, dynamics, and formation of exoplanetary systems. Recent observations by ALMA have revealed an apparent paradox in this field, the presence of radially narrow belts in protoplanetary discs that are likely the birthplaces of planetesimals, and exoKuiper belts nearly four times as wide in mature systems. If the parent planetesimals of this type of debris disc indeed form in these narrow protoplanetary rings via streaming instability where dust is trapped, we propose that this width dichotomy could naturally arise if these dust traps form planetesimals whilst migrating radially, e.g. as caused by a migrating planet. Using the dust evolution software DustPy, we find that if the initial protoplanetary disc and trap conditions favour planetesimal formation, dust can still effectively accumulate and form planetesimals as the trap moves. This leads to a positive correlation between the inward radial speed and final planetesimal belt width, forming belts up to $\sim$100 au over 10 Myr of evolution. We show that although planetesimal formation is most efficient in low viscosity ($\alpha =10^{-4}$) discs with steep dust traps to trigger the streaming instability, the large widths of most observed planetesimal belts constrain $\alpha$ to values $\ge 4\times 10^{-4}$ at tens of au, otherwise the traps cannot migrate far enough. Additionally, the large spread in the widths and radii of exoKuiper belts could be due to different trap migration speeds (or protoplanetary disc lifetimes) and different starting locations, respectively. Our work serves as a first step to link exoKuiper belts and rings in protoplanetary discs.

Accepted for publication in MNRAS. 15 pages,12 figures

References in corpus (39)

• Coagulation, fragmentation and radial motion of solid particles in protoplanetary disks
• Gas- and dust evolution in protoplanetary disks
• Particle Stirring in Turbulent Gas Disks: Including Orbital Oscillations
• Closed-form expressions for particle relative velocities induced by turbulence
• A Steeper than Linear Disk Mass-Stellar Mass Scaling Relation
• Ring shaped dust accumulation in transition disks
• Gaps, Rings, and Non-Axisymmetric Structures in Protoplanetary Disks - From Simulations to ALMA Observations
• The stickiness of micrometer-sized water-ice particles
• A Three-Dimensional View of Turbulence: Constraints on Turbulent Motions in the HD 163296 Protoplanetary Disk using DCO${}^{+}$
• Close-in planetesimal formation by pile-up of drifting pebbles
• Meridional flows in the disk around a young star
• Multiple Disk Gaps and Rings Generated by a Single Super-Earth
• Cavity opening by a giant planet in a protoplanetary disc and effects on planetary migration
• Contacts of Water Ice in Protoplanetary Disks - Laboratory Experiments
• Measuring turbulent motion in planet-forming disks with ALMA: A detection around DM Tau and non-detections around MWC 480 and V4046 Sgr
• Can dead zones create structures like a transition disk?
• The Ophiuchus DIsc Survey Employing ALMA (ODISEA)-III: the evolution of substructures in massive discs at 3-5 au resolution
• Type I Planet Migration in Nearly Laminar Disks
• Turbulence sets the length scale for planetesimal formation: Local 2D simulations of streaming instability and planetesimal formation
• A Complete ALMA Map of the Fomalhaut Debris Disk
• Dust unveils the formation of a mini-Neptune planet in a protoplanetary ring
• Short dissipation times of proto-planetary discs - an artifact of selection effects?
• The evolution of dust in discs influenced by external photoevaporation
• Sticking Properties of Silicates in Planetesimal Formation Revisited
• Planetesimal Population Synthesis: Pebble Flux Regulated Planetesimal Formation
• 3D MHD Simulations of Planet Migration in Turbulent Stratified Disks
• Dust-driven viscous ring-instability in protoplanetary disks
• Numerical simulations of type III planetary migration: III. Outward migration of massive planets
• Ice Grain Collisions in Comparison: CO${}_2$, H${}_2$O and their Mixtures
• How dust fragmentation may be beneficial to planetary growth by pebble accretion
• The Northern Arc of $\epsilon$ Eridani's Debris Ring as Seen by ALMA
• The Mass of Stirring Bodies in the AU Mic Debris Disk Inferred from Resolved Vertical Structure
• A gap in HD 92945's broad planetesimal disc revealed by ALMA
• ALMA observations of the narrow HR 4796A debris ring
• Growing and Trapping Pebbles with Fragile Collisions of Particles in Protoplanetary Disks
• Multiple Rings of Millimeter Dust Emission in the HD 15115 Debris Disk
• X-ray photoevaporation's limited success in the formation of planetesimals by the streaming instability
• Revealing signatures of planets migrating in protoplanetary discs with ALMA multi-wavelength observations
• The fate of planetesimals formed at planetary gap edges

Cited by in corpus (1)

• A "no-drift" runaway pile-up of pebbles in protoplanetary disks II. Characteristics of the resulting planetesimal belt